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1 <html>
2 <head>
3 <title>pcretest specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 <h1>pcretest man page</h1>
7 <p>
8 Return to the <a href="index.html">PCRE index page</a>.
9 </p>
10 <p>
11 This page is part of the PCRE HTML documentation. It was generated automatically
12 from the original man page. If there is any nonsense in it, please consult the
13 man page, in case the conversion went wrong.
14 <br>
15 <ul>
16 <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
17 <li><a name="TOC2" href="#SEC2">OPTIONS</a>
18 <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
19 <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
20 <li><a name="TOC5" href="#SEC5">DATA LINES</a>
21 <li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
22 <li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
24 <li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
25 <li><a name="TOC10" href="#SEC10">CALLOUTS</a>
26 <li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a>
28 <li><a name="TOC13" href="#SEC13">SEE ALSO</a>
29 <li><a name="TOC14" href="#SEC14">AUTHOR</a>
30 <li><a name="TOC15" href="#SEC15">REVISION</a>
31 </ul>
32 <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
33 <P>
34 <b>pcretest [options] [source] [destination]</b>
35 <br>
36 <br>
37 <b>pcretest</b> was written as a test program for the PCRE regular expression
38 library itself, but it can also be used for experimenting with regular
39 expressions. This document describes the features of the test program; for
40 details of the regular expressions themselves, see the
41 <a href="pcrepattern.html"><b>pcrepattern</b></a>
42 documentation. For details of the PCRE library function calls and their
43 options, see the
44 <a href="pcreapi.html"><b>pcreapi</b></a>
45 documentation.
46 </P>
47 <br><a name="SEC2" href="#TOC1">OPTIONS</a><br>
48 <P>
49 <b>-b</b>
50 Behave as if each regex has the <b>/B</b> (show bytecode) modifier; the internal
51 form is output after compilation.
52 </P>
53 <P>
54 <b>-C</b>
55 Output the version number of the PCRE library, and all available information
56 about the optional features that are included, and then exit.
57 </P>
58 <P>
59 <b>-d</b>
60 Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
61 form and information about the compiled pattern is output after compilation;
62 <b>-d</b> is equivalent to <b>-b -i</b>.
63 </P>
64 <P>
65 <b>-dfa</b>
66 Behave as if each data line contains the \D escape sequence; this causes the
67 alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
68 standard <b>pcre_exec()</b> function (more detail is given below).
69 </P>
70 <P>
71 <b>-help</b>
72 Output a brief summary these options and then exit.
73 </P>
74 <P>
75 <b>-i</b>
76 Behave as if each regex has the <b>/I</b> modifier; information about the
77 compiled pattern is given after compilation.
78 </P>
79 <P>
80 <b>-m</b>
81 Output the size of each compiled pattern after it has been compiled. This is
82 equivalent to adding <b>/M</b> to each regular expression. For compatibility
83 with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
84 </P>
85 <P>
86 <b>-o</b> <i>osize</i>
87 Set the number of elements in the output vector that is used when calling
88 <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
89 is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
90 22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
91 changed for individual matching calls by including \O in the data line (see
92 below).
93 </P>
94 <P>
95 <b>-p</b>
96 Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
97 used to call PCRE. None of the other options has any effect when <b>-p</b> is
98 set.
99 </P>
100 <P>
101 <b>-q</b>
102 Do not output the version number of <b>pcretest</b> at the start of execution.
103 </P>
104 <P>
105 <b>-S</b> <i>size</i>
106 On Unix-like systems, set the size of the runtime stack to <i>size</i>
107 megabytes.
108 </P>
109 <P>
110 <b>-t</b>
111 Run each compile, study, and match many times with a timer, and output
112 resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
113 <b>-t</b>, because you will then get the size output a zillion times, and the
114 timing will be distorted. You can control the number of iterations that are
115 used for timing by following <b>-t</b> with a number (as a separate item on the
116 command line). For example, "-t 1000" would iterate 1000 times. The default is
117 to iterate 500000 times.
118 </P>
119 <P>
120 <b>-tm</b>
121 This is like <b>-t</b> except that it times only the matching phase, not the
122 compile or study phases.
123 </P>
124 <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
125 <P>
126 If <b>pcretest</b> is given two filename arguments, it reads from the first and
127 writes to the second. If it is given only one filename argument, it reads from
128 that file and writes to stdout. Otherwise, it reads from stdin and writes to
129 stdout, and prompts for each line of input, using "re&#62;" to prompt for regular
130 expressions, and "data&#62;" to prompt for data lines.
131 </P>
132 <P>
133 When <b>pcretest</b> is built, a configuration option can specify that it should
134 be linked with the <b>libreadline</b> library. When this is done, if the input
135 is from a terminal, it is read using the <b>readline()</b> function. This
136 provides line-editing and history facilities. The output from the <b>-help</b>
137 option states whether or not <b>readline()</b> will be used.
138 </P>
139 <P>
140 The program handles any number of sets of input on a single input file. Each
141 set starts with a regular expression, and continues with any number of data
142 lines to be matched against the pattern.
143 </P>
144 <P>
145 Each data line is matched separately and independently. If you want to do
146 multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
147 etc., depending on the newline setting) in a single line of input to encode the
148 newline sequences. There is no limit on the length of data lines; the input
149 buffer is automatically extended if it is too small.
150 </P>
151 <P>
152 An empty line signals the end of the data lines, at which point a new regular
153 expression is read. The regular expressions are given enclosed in any
154 non-alphanumeric delimiters other than backslash, for example:
155 <pre>
156 /(a|bc)x+yz/
157 </pre>
158 White space before the initial delimiter is ignored. A regular expression may
159 be continued over several input lines, in which case the newline characters are
160 included within it. It is possible to include the delimiter within the pattern
161 by escaping it, for example
162 <pre>
163 /abc\/def/
164 </pre>
165 If you do so, the escape and the delimiter form part of the pattern, but since
166 delimiters are always non-alphanumeric, this does not affect its interpretation.
167 If the terminating delimiter is immediately followed by a backslash, for
168 example,
169 <pre>
170 /abc/\
171 </pre>
172 then a backslash is added to the end of the pattern. This is done to provide a
173 way of testing the error condition that arises if a pattern finishes with a
174 backslash, because
175 <pre>
176 /abc\/
177 </pre>
178 is interpreted as the first line of a pattern that starts with "abc/", causing
179 pcretest to read the next line as a continuation of the regular expression.
180 </P>
181 <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
182 <P>
183 A pattern may be followed by any number of modifiers, which are mostly single
184 characters. Following Perl usage, these are referred to below as, for example,
185 "the <b>/i</b> modifier", even though the delimiter of the pattern need not
186 always be a slash, and no slash is used when writing modifiers. Whitespace may
187 appear between the final pattern delimiter and the first modifier, and between
188 the modifiers themselves.
189 </P>
190 <P>
191 The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
192 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
193 <b>pcre_compile()</b> is called. These four modifier letters have the same
194 effect as they do in Perl. For example:
195 <pre>
196 /caseless/i
197 </pre>
198 The following table shows additional modifiers for setting PCRE options that do
199 not correspond to anything in Perl:
200 <pre>
201 <b>/A</b> PCRE_ANCHORED
204 <b>/f</b> PCRE_FIRSTLINE
205 <b>/J</b> PCRE_DUPNAMES
207 <b>/U</b> PCRE_UNGREEDY
208 <b>/X</b> PCRE_EXTRA
209 <b>/&#60;JS&#62;</b> PCRE_JAVASCRIPT_COMPAT
210 <b>/&#60;cr&#62;</b> PCRE_NEWLINE_CR
211 <b>/&#60;lf&#62;</b> PCRE_NEWLINE_LF
212 <b>/&#60;crlf&#62;</b> PCRE_NEWLINE_CRLF
213 <b>/&#60;anycrlf&#62;</b> PCRE_NEWLINE_ANYCRLF
214 <b>/&#60;any&#62;</b> PCRE_NEWLINE_ANY
215 <b>/&#60;bsr_anycrlf&#62;</b> PCRE_BSR_ANYCRLF
216 <b>/&#60;bsr_unicode&#62;</b> PCRE_BSR_UNICODE
217 </pre>
218 Those specifying line ending sequences are literal strings as shown, but the
219 letters can be in either case. This example sets multiline matching with CRLF
220 as the line ending sequence:
221 <pre>
222 /^abc/m&#60;crlf&#62;
223 </pre>
224 Details of the meanings of these PCRE options are given in the
225 <a href="pcreapi.html"><b>pcreapi</b></a>
226 documentation.
227 </P>
228 <br><b>
229 Finding all matches in a string
230 </b><br>
231 <P>
232 Searching for all possible matches within each subject string can be requested
233 by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
234 again to search the remainder of the subject string. The difference between
235 <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
236 <b>pcre_exec()</b> to start searching at a new point within the entire string
237 (which is in effect what Perl does), whereas the latter passes over a shortened
238 substring. This makes a difference to the matching process if the pattern
239 begins with a lookbehind assertion (including \b or \B).
240 </P>
241 <P>
242 If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
243 empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
244 flags set in order to search for another, non-empty, match at the same point.
245 If this second match fails, the start offset is advanced by one, and the normal
246 match is retried. This imitates the way Perl handles such cases when using the
247 <b>/g</b> modifier or the <b>split()</b> function.
248 </P>
249 <br><b>
250 Other modifiers
251 </b><br>
252 <P>
253 There are yet more modifiers for controlling the way <b>pcretest</b>
254 operates.
255 </P>
256 <P>
257 The <b>/+</b> modifier requests that as well as outputting the substring that
258 matched the entire pattern, pcretest should in addition output the remainder of
259 the subject string. This is useful for tests where the subject contains
260 multiple copies of the same substring.
261 </P>
262 <P>
263 The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
264 output a representation of the compiled byte code after compilation. Normally
265 this information contains length and offset values; however, if <b>/Z</b> is
266 also present, this data is replaced by spaces. This is a special feature for
267 use in the automatic test scripts; it ensures that the same output is generated
268 for different internal link sizes.
269 </P>
270 <P>
271 The <b>/L</b> modifier must be followed directly by the name of a locale, for
272 example,
273 <pre>
274 /pattern/Lfr_FR
275 </pre>
276 For this reason, it must be the last modifier. The given locale is set,
277 <b>pcre_maketables()</b> is called to build a set of character tables for the
278 locale, and this is then passed to <b>pcre_compile()</b> when compiling the
279 regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
280 pointer; that is, <b>/L</b> applies only to the expression on which it appears.
281 </P>
282 <P>
283 The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
284 compiled pattern (whether it is anchored, has a fixed first character, and
285 so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
286 pattern. If the pattern is studied, the results of that are also output.
287 </P>
288 <P>
289 The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
290 <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
291 </P>
292 <P>
293 The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
294 fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
295 facility is for testing the feature in PCRE that allows it to execute patterns
296 that were compiled on a host with a different endianness. This feature is not
297 available when the POSIX interface to PCRE is being used, that is, when the
298 <b>/P</b> pattern modifier is specified. See also the section about saving and
299 reloading compiled patterns below.
300 </P>
301 <P>
302 The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
303 expression has been compiled, and the results used when the expression is
304 matched.
305 </P>
306 <P>
307 The <b>/M</b> modifier causes the size of memory block used to hold the compiled
308 pattern to be output.
309 </P>
310 <P>
311 The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
312 API rather than its native API. When this is done, all other modifiers except
313 <b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is
314 present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions
315 force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
316 </P>
317 <P>
318 The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8
319 option set. This turns on support for UTF-8 character handling in PCRE,
320 provided that it was compiled with this support enabled. This modifier also
321 causes any non-printing characters in output strings to be printed using the
322 \x{hh...} notation if they are valid UTF-8 sequences.
323 </P>
324 <P>
325 If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
326 call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
327 checking of the string for UTF-8 validity.
328 </P>
329 <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
330 <P>
331 Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
332 whitespace is removed, and it is then scanned for \ escapes. Some of these are
333 pretty esoteric features, intended for checking out some of the more
334 complicated features of PCRE. If you are just testing "ordinary" regular
335 expressions, you probably don't need any of these. The following escapes are
336 recognized:
337 <pre>
338 \a alarm (BEL, \x07)
339 \b backspace (\x08)
340 \e escape (\x27)
341 \f formfeed (\x0c)
342 \n newline (\x0a)
343 \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
344 \r carriage return (\x0d)
345 \t tab (\x09)
346 \v vertical tab (\x0b)
347 \nnn octal character (up to 3 octal digits)
348 \xhh hexadecimal character (up to 2 hex digits)
349 \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
350 \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
351 \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
352 \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
353 \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
354 ated by next non alphanumeric character)
355 \C+ show the current captured substrings at callout time
356 \C- do not supply a callout function
357 \C!n return 1 instead of 0 when callout number n is reached
358 \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
359 \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
360 \D use the <b>pcre_dfa_exec()</b> match function
361 \F only shortest match for <b>pcre_dfa_exec()</b>
362 \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
363 \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
364 ated by next non-alphanumeric character)
365 \L call pcre_get_substringlist() after a successful match
366 \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
367 \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
368 \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
369 \P pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
370 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
371 \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
372 \S output details of memory get/free calls during matching
373 \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
374 \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
375 \&#62;dd start the match at offset dd (any number of digits);
376 this sets the <i>startoffset</i> argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
377 \&#60;cr&#62; pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
378 \&#60;lf&#62; pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
379 \&#60;crlf&#62; pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
380 \&#60;anycrlf&#62; pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
381 \&#60;any&#62; pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
382 </pre>
383 The escapes that specify line ending sequences are literal strings, exactly as
384 shown. No more than one newline setting should be present in any data line.
385 </P>
386 <P>
387 A backslash followed by anything else just escapes the anything else. If
388 the very last character is a backslash, it is ignored. This gives a way of
389 passing an empty line as data, since a real empty line terminates the data
390 input.
391 </P>
392 <P>
393 If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
394 different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
395 fields of the <b>pcre_extra</b> data structure, until it finds the minimum
396 numbers for each parameter that allow <b>pcre_exec()</b> to complete. The
397 <i>match_limit</i> number is a measure of the amount of backtracking that takes
398 place, and checking it out can be instructive. For most simple matches, the
399 number is quite small, but for patterns with very large numbers of matching
400 possibilities, it can become large very quickly with increasing length of
401 subject string. The <i>match_limit_recursion</i> number is a measure of how much
402 stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
403 to complete the match attempt.
404 </P>
405 <P>
406 When \O is used, the value specified may be higher or lower than the size set
407 by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
408 the call of <b>pcre_exec()</b> for the line in which it appears.
409 </P>
410 <P>
411 If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
412 API to be used, the only option-setting sequences that have any effect are \B
413 and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
414 <b>regexec()</b>.
415 </P>
416 <P>
417 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
418 of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
419 any number of hexadecimal digits inside the braces. The result is from one to
420 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
421 allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
422 valid Unicode code points, or indeed valid UTF-8 characters according to the
423 later rules in RFC 3629.
424 </P>
425 <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
426 <P>
427 By default, <b>pcretest</b> uses the standard PCRE matching function,
428 <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
429 alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
430 different way, and has some restrictions. The differences between the two
431 functions are described in the
432 <a href="pcrematching.html"><b>pcrematching</b></a>
433 documentation.
434 </P>
435 <P>
436 If a data line contains the \D escape sequence, or if the command line
437 contains the <b>-dfa</b> option, the alternative matching function is called.
438 This function finds all possible matches at a given point. If, however, the \F
439 escape sequence is present in the data line, it stops after the first match is
440 found. This is always the shortest possible match.
441 </P>
442 <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
443 <P>
444 This section describes the output when the normal matching function,
445 <b>pcre_exec()</b>, is being used.
446 </P>
447 <P>
448 When a match succeeds, pcretest outputs the list of captured substrings that
449 <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
450 the whole pattern. Otherwise, it outputs "No match" or "Partial match"
451 when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
452 respectively, and otherwise the PCRE negative error number. Here is an example
453 of an interactive <b>pcretest</b> run.
454 <pre>
455 $ pcretest
456 PCRE version 7.0 30-Nov-2006
458 re&#62; /^abc(\d+)/
459 data&#62; abc123
460 0: abc123
461 1: 123
462 data&#62; xyz
463 No match
464 </pre>
465 Note that unset capturing substrings that are not followed by one that is set
466 are not returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In
467 the following example, there are two capturing substrings, but when the first
468 data line is matched, the second, unset substring is not shown. An "internal"
469 unset substring is shown as "&#60;unset&#62;", as for the second data line.
470 <pre>
471 re&#62; /(a)|(b)/
472 data&#62; a
473 0: a
474 1: a
475 data&#62; b
476 0: b
477 1: &#60;unset&#62;
478 2: b
479 </pre>
480 If the strings contain any non-printing characters, they are output as \0x
481 escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
482 pattern. See below for the definition of non-printing characters. If the
483 pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
484 the the rest of the subject string, identified by "0+" like this:
485 <pre>
486 re&#62; /cat/+
487 data&#62; cataract
488 0: cat
489 0+ aract
490 </pre>
491 If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
492 matching attempts are output in sequence, like this:
493 <pre>
494 re&#62; /\Bi(\w\w)/g
495 data&#62; Mississippi
496 0: iss
497 1: ss
498 0: iss
499 1: ss
500 0: ipp
501 1: pp
502 </pre>
503 "No match" is output only if the first match attempt fails.
504 </P>
505 <P>
506 If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
507 data line that is successfully matched, the substrings extracted by the
508 convenience functions are output with C, G, or L after the string number
509 instead of a colon. This is in addition to the normal full list. The string
510 length (that is, the return from the extraction function) is given in
511 parentheses after each string for <b>\C</b> and <b>\G</b>.
512 </P>
513 <P>
514 Note that whereas patterns can be continued over several lines (a plain "&#62;"
515 prompt is used for continuations), data lines may not. However newlines can be
516 included in data by means of the \n escape (or \r, \r\n, etc., depending on
517 the newline sequence setting).
518 </P>
520 <P>
521 When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
522 means of the \D escape sequence or the <b>-dfa</b> command line option), the
523 output consists of a list of all the matches that start at the first point in
524 the subject where there is at least one match. For example:
525 <pre>
526 re&#62; /(tang|tangerine|tan)/
527 data&#62; yellow tangerine\D
528 0: tangerine
529 1: tang
530 2: tan
531 </pre>
532 (Using the normal matching function on this data finds only "tang".) The
533 longest matching string is always given first (and numbered zero).
534 </P>
535 <P>
536 If <b>/g</b> is present on the pattern, the search for further matches resumes
537 at the end of the longest match. For example:
538 <pre>
539 re&#62; /(tang|tangerine|tan)/g
540 data&#62; yellow tangerine and tangy sultana\D
541 0: tangerine
542 1: tang
543 2: tan
544 0: tang
545 1: tan
546 0: tan
547 </pre>
548 Since the matching function does not support substring capture, the escape
549 sequences that are concerned with captured substrings are not relevant.
550 </P>
551 <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
552 <P>
553 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
554 indicating that the subject partially matched the pattern, you can restart the
555 match with additional subject data by means of the \R escape sequence. For
556 example:
557 <pre>
558 re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
559 data&#62; 23ja\P\D
560 Partial match: 23ja
561 data&#62; n05\R\D
562 0: n05
563 </pre>
564 For further information about partial matching, see the
565 <a href="pcrepartial.html"><b>pcrepartial</b></a>
566 documentation.
567 </P>
568 <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
569 <P>
570 If the pattern contains any callout requests, <b>pcretest</b>'s callout function
571 is called during matching. This works with both matching functions. By default,
572 the called function displays the callout number, the start and current
573 positions in the text at the callout time, and the next pattern item to be
574 tested. For example, the output
575 <pre>
576 ---&#62;pqrabcdef
577 0 ^ ^ \d
578 </pre>
579 indicates that callout number 0 occurred for a match attempt starting at the
580 fourth character of the subject string, when the pointer was at the seventh
581 character of the data, and when the next pattern item was \d. Just one
582 circumflex is output if the start and current positions are the same.
583 </P>
584 <P>
585 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
586 result of the <b>/C</b> pattern modifier. In this case, instead of showing the
587 callout number, the offset in the pattern, preceded by a plus, is output. For
588 example:
589 <pre>
590 re&#62; /\d?[A-E]\*/C
591 data&#62; E*
592 ---&#62;E*
593 +0 ^ \d?
594 +3 ^ [A-E]
595 +8 ^^ \*
596 +10 ^ ^
597 0: E*
598 </pre>
599 The callout function in <b>pcretest</b> returns zero (carry on matching) by
600 default, but you can use a \C item in a data line (as described above) to
601 change this.
602 </P>
603 <P>
604 Inserting callouts can be helpful when using <b>pcretest</b> to check
605 complicated regular expressions. For further information about callouts, see
606 the
607 <a href="pcrecallout.html"><b>pcrecallout</b></a>
608 documentation.
609 </P>
610 <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
611 <P>
612 When <b>pcretest</b> is outputting text in the compiled version of a pattern,
613 bytes other than 32-126 are always treated as non-printing characters are are
614 therefore shown as hex escapes.
615 </P>
616 <P>
617 When <b>pcretest</b> is outputting text that is a matched part of a subject
618 string, it behaves in the same way, unless a different locale has been set for
619 the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
620 function to distinguish printing and non-printing characters.
621 </P>
622 <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
623 <P>
624 The facilities described in this section are not available when the POSIX
625 inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
626 specified.
627 </P>
628 <P>
629 When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
630 compiled pattern to a file, by following the modifiers with &#62; and a file name.
631 For example:
632 <pre>
633 /pattern/im &#62;/some/file
634 </pre>
635 See the
636 <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
637 documentation for a discussion about saving and re-using compiled patterns.
638 </P>
639 <P>
640 The data that is written is binary. The first eight bytes are the length of the
641 compiled pattern data followed by the length of the optional study data, each
642 written as four bytes in big-endian order (most significant byte first). If
643 there is no study data (either the pattern was not studied, or studying did not
644 return any data), the second length is zero. The lengths are followed by an
645 exact copy of the compiled pattern. If there is additional study data, this
646 follows immediately after the compiled pattern. After writing the file,
647 <b>pcretest</b> expects to read a new pattern.
648 </P>
649 <P>
650 A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
651 name instead of a pattern. The name of the file must not contain a &#60; character,
652 as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
653 characters.
654 For example:
655 <pre>
656 re&#62; &#60;/some/file
657 Compiled regex loaded from /some/file
658 No study data
659 </pre>
660 When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
661 the usual way.
662 </P>
663 <P>
664 You can copy a file written by <b>pcretest</b> to a different host and reload it
665 there, even if the new host has opposite endianness to the one on which the
666 pattern was compiled. For example, you can compile on an i86 machine and run on
667 a SPARC machine.
668 </P>
669 <P>
670 File names for saving and reloading can be absolute or relative, but note that
671 the shell facility of expanding a file name that starts with a tilde (~) is not
672 available.
673 </P>
674 <P>
675 The ability to save and reload files in <b>pcretest</b> is intended for testing
676 and experimentation. It is not intended for production use because only a
677 single pattern can be written to a file. Furthermore, there is no facility for
678 supplying custom character tables for use with a reloaded pattern. If the
679 original pattern was compiled with custom tables, an attempt to match a subject
680 string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
681 Finally, if you attempt to load a file that is not in the correct format, the
682 result is undefined.
683 </P>
684 <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
685 <P>
686 <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrematching</b>(3),
687 <b>pcrepartial</b>(d), <b>pcrepattern</b>(3), <b>pcreprecompile</b>(3).
688 </P>
689 <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
690 <P>
691 Philip Hazel
692 <br>
693 University Computing Service
694 <br>
695 Cambridge CB2 3QH, England.
696 <br>
697 </P>
698 <br><a name="SEC15" href="#TOC1">REVISION</a><br>
699 <P>
700 Last updated: 12 April 2008
701 <br>
702 Copyright &copy; 1997-2008 University of Cambridge.
703 <br>
704 <p>
705 Return to the <a href="index.html">PCRE index page</a>.
706 </p>


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